This game breeds toxicity because there's no threat of violence for your actions in a team environment.
Take Hockey for example... if people acted like they do playing league while playing hockey, they'd be pummeled by both teams.
Nobody cares about their accounts, really. The high elo players who are toxic are good enough to just start/buy new account and get back to where they were. The low elo players.. the same thing. Nobody gives two fucks about their fellow player because since this games inception, it's been nothing but a push for "I NEED TO CARRY". The fact that there's a SOLO QUEUE right there tells you that its ALL ABOUT ME. SOLO. CARRYING. There's no teamplay, no strategy in pick and bans, there's nothing happening to promote cooperation whatsoever in this game.
What do they grade you on in game? Well, mostly your OWN PERFORMANCE. HOW WELL DID YOU CARRY?!? It should be setup to reward you better for things like PLACING WARDS or CORRECTLY PINGING DANGER (yes, you should get points for using the question mark ping in your lane when an enemy is missing).
The idiots at Riot Games have their head shoved so far up their politically correct asses that they don't see how fucking terrible of an experience it is to queue up alone and get matched with 4 other random fuckers who are all trying to do 1 thing and 1 thing only... "CARRY".
"Don't worry. I'll outplay everyone in this game and carry us all to victory."
Fuck that mentality you fucking idiots.
Riot loves the toxicity excuse to ban an account. They just tilt that person further until they start again and dish out more money for champs and skins on a new account.
Fuck Riot and their immoral revenue from toxic players. They'll never change it, it makes them too much money.